NHB???Those Russians are tough tough bastards, id say far naturally tougher than juice heads like overeem. Also Vitali is a former world champion kick boxer so knows more than just how to punch.
WHoever said boxing is the weakest sport or some shit even the likes of Randy Couture say boxings the toughest as you take far more damage as you re constantly swapping blows.
But hey this is getbig, we all know better than anyone about anything.